World's store of data calculated

Emma Woollacott, 11th February 2011

A University of Southern California scientist says he's worked out just how much information is being stored by the human race - and there's an awful lot of it. Two hundred and ninety-five exabytes, to be precise.

That is an awful lot of Facebook posts and porn movies - as well as great literature, because the figure includes 'analog' information as well. If a grain of sand is a bit of information, says Martin Hilbert, it would mean 315 times the amount of sand in the world for every person in the world.

"We live in a world where economies, political freedom and cultural growth increasingly depend on our technological capabilities," says Hilbert. "This is the first time-series study to quantify humankind's ability to handle information."

But let's not get too swell-headed about our general knowletge - the 295-exabyte figure is still less than one percent of the information that is stored in all the DNA molecules of a human being.

When historians put a date to the beginning of the digital age, says Hilbert, it's likely to be 2002, the year in which worldwide digital storage capacity first overtook total analog capacity. And, boy, did it take over - by 2007, almost 94 percent of our memory was in digital form.

In the same year, apparently, humankind sent 1.9 zettabytes of information through broadcast technology such as televisions and GPS. That's equivalent to every person in the world reading 174 newspapers every day.

"These numbers are impressive, but still miniscule compared to the order of magnitude at which nature handles information," says Hilbert.

"Compared to nature, we are but humble apprentices. However, while the natural world is mind-boggling in its size, it remains fairly constant. In contrast, the world's technological information processing capacities are growing at exponential rates."